Opening and closing system for oil path of linear compressor

ABSTRACT

An opening and closing system for an oil path of a linear compressor that facilitates smooth oil supply during the operation of the compressor and has the oil which has been supplied to the compressor partly remained therein when suspending the operation of the compressor for smooth lubrication when re-operating the compressor includes a hermetic vessel in which oil is filled in a bottom part thereof, a frame disposed in the hermetic vessel and communicating with a first oil groove and a second oil groove, a cylinder inserted into a through hole formed in a predetermined portion of the frame, a piston linearly reciprocating by the driving of a motor by being inserted into the cylinder, the second oil groove being formed on a portion of an outer circumferential surface of the piston, an exhaust cover coupled to one side of the cylinder, an oil supplier disposed at the frame for pumping out oil and communicating with the first oil groove through an oil inflow path, and a switching means formed between the first oil groove and the oil inflow path for opening and closing the oil inflow path.

TECHNICAL FIELD

The present invention relates to a linear compressor, and moreparticularly to an opening and closing system for an oil path of alinear compressor capable of facilitating smooth oil supply duringoperation of the compressor and smooth lubrication by an oil whichremains in the compressor when re-operating the compressor by having thesupplied oil partly remained therein when the operation of thecompressor is suspended.

BACKGROUND ART

Recently, as in home appliances such as a refrigerator and anair-conditioner, etc. high-efficiency and power-saving products havebeen produced, the study for developing a compressor constituting arefrigerating cycle machine which is installed in a refrigerator or anair-conditioner is also being lively made.

A linear compressor, which is one of the compressors for sucking andcompressing low-pressure air and exhausting the compressed air at highpressure, is illustrated in FIG. 1.

As shown therein, the linear compressor includes a hermetic vessel 1 inwhich a predetermined amount of oil is filled, a frame 10 formed in apredetermined shape and disposed in the hermetic vessel 1, a cylinder 20inserted into the frame 10, an inner stator assembly 30 coupled with oneside portion of the frame 10 for constituting a motor, an outer statorassembly 31 coupled with the inner stator assembly 30 at a predetermineddistance, a magnet 32 inserted between the inner and outer statorassemblys 30, 31, and a piston 40 inserted into the cylinder 20 andcoupled to a magnet frame 33 to which the magnet 32 is fixedlyconnected, and reciprocating in accordance with the linear movement ofthe magnet 32, wherein there is formed a refrigerant oil path F in thepiston 40 through which a refrigerant gas is flowed.

Further, a predetermined-shaped cover 50 is engaged to the other side ofthe frame 10, and at an inner part of the cover 50 a main spring 51 isprovided at both sides of the magnet frame 33 coupled to the piston 40and thus elastically supports the reciprocation of the piston 40.

While, an exhaust cover 60 formed in a cap type is coupled to one sideof the cylinder 20 and an exhaust valve assembly 61 is insertedlydisposed in an inner portion of the exhaust cover 60, the exhaust valveassembly 61 switching the one side of the cylinder 20, an suction valve62 which switches according to the suction of the gas is coupled to anend portion of the piston 40, and an oil supplier 70 which supplies oilto components to be slid to each other is disposed at a lower part ofthe frame 10.

In the operation of the conventional linear compressor, when an electriccurrent is applied to the motor, the magnet 32 linearly reciprocates andthe linear movement accordingly travels through the magnet frame 33 tothe piston 40 which also accordingly reciprocates in the cylinder 20.

Here, the refrigerant gas which is flowed into the hermetic vessel 1 inaccordance with the linear operation of the piston 40 is flowed into thecylinder 20 through the refrigerant oil path F provided in the piston40, compressed therein and then exhausted through the exhaust valveassembly 61 and the exhaust cover 60, the above process being repeatedlyperformed.

Further, in order to achieve the smooth sliding performed while thepiston 40 is being reciprocating in the cylinder 20 and also to radiatethe heat generated during the compression of the refrigerant gas, theoil pumped out by the oil supplier 70 is supplied to components, forexample, which are disposed between the cylinder. 20 and the piston 40.

Here, in the oil supply system in which the oil pumped out by the oilsupplier 70 circulates, a first oil groove 12 is formed at predeterminedsize on a portion of an inner circumferential surface of a through hole11 of the frame 10 to which the cylinder 20 is inserted, a second oilgroove 41 is formed at predetermined size on a portion of an outercircumferential surface of the piston 40 inserted into the cylinder 20,and an oil pass hole 21 is provided in the cylinder 20 so that the firstoil groove 12 communicates with the second oil groove 41. In addition, aring-shaped oil circular path 13 is formed by the exhaust cover 60connected with an outer circumferential portion of the cylinder 20, thethrough hole 11 and the cylinder 20 when the cylinder 20 is insertedinto the through hole 11 of the frame 10, the oil circular path 13communicating with the first oil groove 12 through an oil communicatingpath 14 formed on a portion of the inner circumferential surface of thethrough hole 11.

Further, an oil inflow path 15 is formed at a portion of the frame 10 sothat the oil pumped out in the oil supplier 70 is flowed to the firstoil groove 12, and an oil discharge hole 17 is formed at a side portionof the oil circular path 13 so as for the oil which has circulatedthrough the oil circular path 13 to be discharged to a bottom part ofthe hermetic vessel 1.

In the thusly described oil supply system of the convention linearcompressor, as shown in FIG. 2, in the operation of the compressor, whenthe oil is pumped out in the oil supplier 70 due to vibrations generatedin the process of which the compressor compresses the refrigerant gaswhile reciprocating, the pumped oil is flowed into the first oil groove12 through the oil inflow path 15 and then flowed to the oil pass hole21 and the second oil groove 41, so that the flowed oil serves as alubricant between the piston 40 and the cylinder 20 and alsorefrigerates the heat generated from the motor.

Further, the oil passed through the first and second oil grooves 12, 41is flowed into the oil circular path 13 through the oil communicatingpath 14, heated parts of the exhaust cover 60 and the cylinder 20 arerefrigerated by the refrigerant gas which is exhausted when the oilflowed to the path 13 circulates through the oil circular path 13, andthe oil flowed to the oil circular path 13 drops to the bottom part ofthe hermetic vessel 1 in which a predetermined amount of oil is filledand such oil continuously circulates by the above-described process.

In addition, numerals 34 and 2 denote a coil assembly and a suctionpipe, respectively.

However, when the operation of the compressor is suspended, the oilbeing supplied is returned to the bottom part of the vessel 1 due to itsself weight. Therefore, when the compressor is restarted to operate insuch condition, no oil remains in a portion, for example, between thecylinder and the piston where friction occurs, and thus the operation isperformed in a non-lubricative state, which results in abrasion of thecomponents in the system as well as friction loss and also becomes aproblem of generation of overload in the initial state of there-operation.

Further, when the pressure of a compression chamber which compresses thegas increases as the piston moves to a top dead center by the driving ofthe motor, the high-pressure refrigerant gas may leak from a gap betweenthe piston and the cylinder and be flowed into the oil path. In thiscase, when the high-pressure refrigerant gas is flowed to the oilsupplier side, there is produced noises caused by, for example, acavitation.

DISCLOSURE OF THE INVENTION

Accordingly, an object of the present invention is to provide an openingand closing system for an oil path of a linear compressor thatfacilitates smooth oil supply during the operation of the compressor andhas the oil which has been supplied to the compressor partly remainedtherein when suspending the operation of the compressor for smoothlubrication when re-operating the compressor. To achieve the aboveobject, there is provided an opening and closing system for an oil pathof a linear compressor which includes a hermetic vessel in which oil isfilled in a bottom part thereof, a frame disposed in the hermetic vesseland communicating with a first oil groove and a second oil groove, acylinder inserted into a through hole formed in a predetermined portionof the frame, a piston linearly reciprocating by the driving of a motorby being inserted into the cylinder, the second oil groove being formedon a portion of an outer circumferential surface of the piston, anexhaust cover coupled to one side of the cylinder, an oil supplierdisposed at the frame for pumping out oil and communicating with thefirst oil groove through an oil inflow path, and a switching meansprovided between the first oil groove and the oil inflow path foropening and closing the oil inflow path.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention andtogether with the description serve to explain the principles of theinvention.

In the drawings:

FIG. 1. is a cross-sectional view illustrating an example of aconventional linear compressor;

FIG. 2. is a front view of the conventional linear compressor whichpartially illustrates a cross-sectional view of an oil supply system ofthe conventional linear compressor;

FIG. 3 is a front view sectionally illustrating a part of a linearcompressor according to the present invention;

FIG. 4 is a perspective view illustrating a first embodiment of answitching means of an opening and closing system for an oil path of thelinear compressor according to the present invention;

FIG. 5 is a perspective view illustrating a second embodiment of aswitching means of the opening and closing system for the oil path ofthe linear compressor according to the present invention;

FIG. 6 is a perspective view illustrating a third embodiment of aswitching means of the opening and closing system for the oil path ofthe linear compressor according to the present invention;

FIG. 7A is a cross-sectional view illustrating an oil flow state whenthe compressor is active in the opening and closing system for the oilpath of the linear compressor according to the present invention; and

FIG. 7B is a cross-sectional view illustrating an oil flow state whenthe compressor is not active in the opening and closing system for theoil path of the linear compressor according to the present invention.

MODES FOR CARRYING OUT THE PREFERRED EMBODIMENTS

With reference to the accompanying drawings, an opening and closingsystem for an oil path of a linear compressor according to the presentinvention will be described in detail. Here, the components which arethe same as those of the conventional art are labelled with the samereference numbers.

As shown in FIG. 3, the opening and closing system for the oil path ofthe linear compressor according to the present invention is providedwith a hermetic vessel 1 in which oil is filled at a bottom partthereof, a frame 10 disposed in the hermetic vessel 1, a cylinder 20inserted into a through hole 11 formed in a portion of the frame, apiston 40 inserted to a portion of the cylinder 20 and reciprocating inaccordance with the driving of a motor, an exhaust cover 60 engaged witha side portion of the cylinder 20 by covering the cylinder 20, and anoil supplier 70 disposed at a bottom part of the frame 10 for pumpingout oil.

Further, the opening and closing system for the oil path of the linearcompressor includes a first oil groove 12 formed on a portion of aninner circumferential surface of the through hole 11 in the frame 10, asecond oil groove 41 formed on a portion of an outer circumferentialsurface of the piston 40, an oil pass hole 21 penetratingly formed inthe cylinder 20 so that the first oil groove 12 communicates with thesecond oil groove 41, a ring-shaped oil circular path 13 formed by anouter circumferential portion of the cylinder 20, the through hole 11 inthe frame 10 and the exhaust cover 60, an oil communicating path 14which communicates the oil circular path 13 to the first oil groove 12,an oil discharge hole 17 which communicates with the oil circular path13 so as for the oil which has circulated through the oil circular path13 to return to the hermetic vessel 1, an oil inflow path 15 whichcommunicates a discharge side of the oil supplier 70 to the first oilpath 12 so that the oil pumped out by the oil supplier 70 is flowed tothe first oil groove 12, and a switching means 80, 180, 280 provided atthe first oil groove 12, the switching means enabling the oil from theoil inflow path 15 to flow to the side of the first oil groove 12 duringthe operation of the compressor and blocking out the oil flowed into thefirst oil groove 12 when the compressor is not active so that the oil isnot flowed into the oil inflow path 15 due to its self weight.

More specifically, since the first oil groove 12 is formed on thespecific portion of the inner circumferential surface of the throughhole 11 at predetermined size, when the cylinder 20 is inserted into thethrough hole 11 of the frame 10, the first oil groove 12 takes the shapeof a ring with the periphery of the cylinder 20, an upper part of thering-shaped first oil groove 12 communicating with the oil communicatingpath 14 while a lower part thereof communicating with the oil inflowpath 15.

Further, the oil path hole 21 which communicates with first oil groove12 is formed in a predetermined portion of the cylinder 20.

FIGS. 4 through 6 respectively illustrate various kinds of the switchingmeans 80, 180, 280. As shown therein, the switching means 80, 180, 280consists of a plate 81, 181, 281 having predetermined thickness and sizeand curvedly formed with curvature corresponding to an innercircumferential surface of the first oil groove 12 and at least onehinge protrusion 82, 182, 282 formed at a side portion of the plate 81,181, 281 and serving as a hinge by being tightly stuck to a portion ofthe outer circumferential surface of the cylinder 20. Thus, when theswitching means 80, 180, 280 is inserted to the first oil groove 12, theplate 81, 181, 281 blocks the oil inflow path 15 and the hingeprotrusion 82, 182, 282 is closely fixed to the portion of the outercircumferential surface of the cylinder 20.

Specifically, as shown in FIG. 4, a first embodiment of the switchingmeans consists of a plate 81 having predetermined thickness and size andcurvedly formed with the curvature corresponding to the innercircumferential surface of the first oil groove 12 and the hingeprotrusion 82 consisting of a couple of portions upwardly protruded fromboth ends of one side portion of the plate 81 at a predetermined length,each end of the portions of the hinge protrusion 82 being curvedlyformed. The ends of the two protruding parts are inwardly curved towarda longitudinal center line of the plate, respectively, and curved facingto each other.

As shown in FIG. 5, a second embodiment of the switching means consistsof a plate 181 having predetermined thickness and size and curvedlyformed with the curvature corresponding to the inner circumferentialsurface of the first oil groove 12 and a hinge protrusion 182 formed bywhich a embossing is formed at the end of one side portion of the plate181 at a predetermined height. Further, as shown in FIG. 6, a thirdembodiment of the switching means consists of a plate 281 havingpredetermined thickness and size and curvedly formed with the curvaturecorresponding to the inner circumferential surface of the first oilgroove 12 and a hinge protrusion 282 upwardly protruded from apredetermined portion of the end of one side portion of the plate 281,an end portion of the hinge protrusion 282 being curvedly formed. Theend portion of the hinge protrusion is inwardly curved inside of theplate.

In such opening and closing system for the oil path of the linearcompressor according to the present invention, when an electric currentis applied to the motor, the magnet 32 linearly reciprocates and thelinear reciprocation effect accordingly is transmitted through themagnet frame 33 to the piston 40 which also accordingly reciprocates inthe cylinder 20.

Here, the refrigerant gas which is flowed into the hermetic vessel 1 inaccordance with the linear reciprocation of the piston 40 is flowed intothe cylinder 20 through the refrigerant oil path F provided in thepiston 40, compressed therein and then exhausted through the exhaustvalve assembly 61 and the exhaust cover 60, the above process beingrepeatedly performed.

When the oil is pumped out in the oil supplier 70 by the vibrationsgenerated in the process of which the compressor compresses therefrigerant gas while reciprocating, the pumped oil is flowed into thefirst oil groove 12 through the oil inflow path 15.

Specifically, in the opening and closing system for the oil path in moredetail, as shown in FIG. 7A, the switching means 80, 180, 280 opens theoil inflow path 15 while pivotally moving upon the hinge protrusion 82,182, 282 by the pumping of the oil and thus the oil is flowed to theside of the first oil groove 12. Further, the oil flowed into the firstoil groove 12 is continuously flowed to the oil pass hole 21 and thenthe second oil groove 41 to thereby be supplied between the piston 40and the cylinder 20 for bringing to the lubricating and refrigeratingeffects.

In addition, the oil which has passed through the first and second oilgrooves 12, 41 flows into the oil circular path 13 via the oilcommunicating path 14, then circulates through the oil circular path 13and drops through the oil discharge hole 17 to the bottom part of thehermetic vessel 1 in which the predetermined amount of oil is filled andsuch oil continuously circulates by the above process.

On the other hand, when the operation of the compressor is suspended,the oil pumping of the oil supplier 70 is accordingly stopped and thusthe oil supplied between the piston 40 and the cylinder 20 returns tothe bottom part of the hermetic vessel 1 due to its self weight. At thistime, in the opening and closing system for the oil path as shown inFIG. 7B, since the switching means 80, 180, 280 pivotally moves upon thehinge protrusion 82, 182, 282 and thus blocks the oil inflow path 15 byits self weight, the oil returning to the bottom part of the hermeticvessel 1 remains in the first and second grooves 12, 41.

Accordingly, when the operation of the compressor resumes, the oilremaining in the first and second grooves 12, 41 lubricates portions, tobe slid to each other, of the components disposed, for example, betweenthe cylinder 20 and the piston 40 and also refrigerates the heatgenerated by the motor. Here, it is noted that it takes about 4 to 5seconds for the oil filled in the bottom part of the hermetic vessel 1to be supplied to the slid portions, and it takes about 16 seconds forthe oil to return to the bottom part of the hermetic vessel 1 due to itsself weight when suspending the operation of the compressor.

As described above, in the opening and closing system for the oil pathof the linear compressor according to the present invention, the oil issmoothly supplied to the compressor during the operation. Further, sincethe supplied oil partly remains in the frame after suspending theoperation of the compressor, the oil remaining therein serves as thelubricant for the components, for example, between the cylinder and thepiston in the resumption of the operation of the compressor for therebypreventing the abrasion and friction loss of the components which mayoccur in the initial state of the re-operation and eventually improvingthe compression efficiency. In addition, since the switching means opensby the oil pressure and thus the oil is supplied to the frictionsurfaces of the components in the normal operation of the compressor,and the switching means keeps the leaking refrigerant from being flowedbackward to the oil supplier, although the leaking refrigerant at thehigh pressure is flowed to the oil path, the opening and closing systemfor the oil path according to the present invention prevents the noisecaused by the leakage of the high-pressure refrigerant gas.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the opening and closingsystem for the oil path of the linear compressor of the presentinvention without departing from the spirit or scope of the invention.Thus, it is intended that the present invention cover the modificationsand variations of this invention provided they come within the scope ofthe appended claims and their equivalents.

What is claimed is:
 1. An opening and closing system for an oil path ofa linear compressor, comprising: a hermetic vessel in which oil isfilled in a bottom part thereof; a frame disposed in the hermetic vesseland communicating with a first oil groove and a second oil groove; acylinder inserted into a through hole formed in a predetermined portionof the frame; a piston linearly reciprocating by the driving of a motorby being inserted into the cylinder, the second oil groove being formedon a portion of an outer circumferential surface of the piston; anexhaust cover coupled to one side of the cylinder; an oil supplierdisposed at the frame for pumping out oil and communicating with thefirst oil groove through an oil inflow path; and a switch providedbetween the first oil groove and the oil inflow path for opening andclosing the oil inflow path.
 2. The opening and closing system for theoil path of the linear compressor according to claim 1, wherein theswitch comprises a plate having predetermined thickness and size andcurvedly formed with a curvature corresponding to an innercircumferential surface of the first oil groove and at least one hingeprotrusion formed at a side portion of the plate and serving as a hingeby being tightly stuck to a portion of an outer circumferential surfaceof the cylinder.
 3. The opening and closing system for the oil path ofthe linear compressor according to claim 2, wherein the hinge protrusioncomprises two parts upwardly protruded from both ends of one sideportion of the plate at a predetermined length, each end of the partsthereof being curved.
 4. The opening and closing system for the oil pathof the linear compressor according to claim 3, wherein the ends of thetwo protruding parts are inwardly curved toward a longitudinal centerline of the plate, respectively.
 5. The opening and closing system forthe oil path of the linear compressor according to claim 4, wherein theends of the two protruding part are curved facing to each other.
 6. Theopening and closing system for the oil path of the linear compressoraccording to claim 2, wherein the hinge protrusion is formed by anembossing formed at the end of one side portion of the plate at apredetermined height.
 7. The opening and closing system for the oil pathof the linear compressor according to claim 2, wherein the hingeprotrusion is upwardly protruded from a predetermined part of the end ofone side portion of the plate, an end portion of the hinge protrusionbeing curved.
 8. The opening and closing system for the oil path of thelinear compressor according to claim 7, wherein the end portion of thehinge protrusion is inwardly curved inside of the plate.
 9. A linearcompressor comprising: a frame having inner walls forming a cylindricalthrough hole, the inner walls having a frame groove formed at an innersurface thereof, the frame groove being connected with an opening of anoil flow path formed within the frame; a hollow cylinder positionedwithin the through hole of the frame, the cylinder having an oil passhole formed through a lateral surface thereof; a piston positionedwithin the cylinder, the piston having a piston groove formed at alateral outer surface thereof; and a switch located within the framegroove to operatively open or close the oil inflow path of the frame;whereby the oil inflow path, the frame groove, the oil pass hole, andthe piston groove create an inflow passage for oil being regulated bythe switch.
 10. The linear compressor of claim 9, wherein, the frame hasan opposing frame groove formed at an inner surface of the inner wallsopposing the frame groove, the opposing frame groove being connectedwith an oil outflow path formed within the frame; the cylinder has anopposing oil pass hole formed through a lateral surface of the hollowcylinder opposing the oil pass hole; and the piston has an opposingpiston groove formed at a lateral outer surface of the piston opposingthe piston oil groove; whereby the oil outflow path, the opposing framegroove, the opposing oil pass hole and the opposing piston oil groovecreate an outflow passage for oil.
 11. The linear compressor of claim 9,wherein the switch comprises: a curved plate having a curvaturecorresponding to that of the frame groove, and having a lengthsufficient to cover the opening of the oil inflow path; and a protrusionformed at one end of the curved plate, the protrusion contacting with anouter lateral surface of the cylinder to act as a hinge at which thecurved plate moves to open or close the oil inflow path according to aflow of oil passing therethrough.
 12. A linear compressor comprising: aframe having inner walls forming a cylindrical through hole, the innerwalls having a frame groove formed at an inner surface thereof, theframe groove connected with an opening of an oil inflow path formedwithin the frame; an oil supplier connected to the frame for supplyingoil into the oil inflow path; a hollow cylinder positioned within thethrough hole of the frame; a piston operatively connected to frame andpositioned within the cylinder; and a valve located within the framegroove to operatively open or close the opening of the oil inflow pathof the frame according to a flow of oil being supplied by the oilsupplier.